PEDIATRIC DENTiSTRY/Copyright © 1987 by The American Academy of Pediatric Dentistry Volume 9 Number 2 CAS

Asymmetrical tooth defects observed in hypoplastic primary teeth and amelogenesis imperfecta: case reports

Anne L. Symons, MDS J.P. Gage, BDS, PhD, HDD, FDS, FRACDS

Abstract Factors that may disturb ameloblasts and result in Tworare cases of asymmetricaltooth destruction affecting their producing hypoplastic enamel include genetic the primarydentition and1 case of hypoplastic,vertical striping causes, nutritional deficiency, maternal illnesses, birth X-linked amelogenesisimperfecta which affects the permanent injury, and trauma (Kreshover et al. 1958). dentition in an asymmetricalmanner, are presented. The etiology This paper presents 2 unusual cases of tooth de- of the conditionsare discussedwith respect to inheritance,pre- struction and 1 case of hypoplastic amelogenesis im- eruptiveand posteruptiveinfluences. The asymmetricalgross tooth destruction reported in the 2 primarydentitions maybe multi- perfecta and discusses the possible reasons for the factorial in origin but genetic influencescannot be excluded. atypical distribution of defects.

Variations in the number and form of teeth Case 1 are, in general, genetically determined, but modifi- A 4-year-old Caucasian female was referred to cations may also arise as a result of a numberof other the pedodontic clinic for managementof gross enam- influences. For example, the absence of teeth such as el erosion and severe wear of the primary teeth on lateral incisors or third molars may be an inherited the left side. anomaly--as may other conditions such as amelo- The medical history revealed no significant or genesis imperfecta and dentinal dysplasia. On the relevant illnesses. The patient had not received any other hand, pre-eruptive influences such as systemic radiation treatment, was born full term, and was of illnesses or local trauma may result in alteration of average height and weight. The history of the preg- the tooth bud components during tooth formation. nancy and postnatal period was uneventful. No un- Dental structures generally are well protected usual oral habits were elicited and the diet was well from damaging influences during intrauterine life balanced with a moderate intake of sucrose, mainly but children with premature or traumatic births tend in liquid form. The patient resided in a nonfluori- to have a higher incidence of dental anomalies in the dated area and had not taken fluoride supplements. primary dentition (Rosenzweig and Sahar 1962). Kre- As an infant the child favored sleeping on her left shover et al. (1958) examined the prevalence of de- side. velopmental dental abnormalities in primary teeth The mother reported that the primary teeth in and concluded they were more common than pre- the left quadrant were stained, dull, and failed to viously thought. Microscopic examination of the teeth erupt completely. At the time of eruption they were of both jaws showed a prominent incremental line defective, with soft enamel which chipped easily, ex- extending over the incisal and occlusal portions of posing the dentinal surface. Maintaining good oral the deciduous anterior and posterior teeth. Rosen- hygiene around the affected teeth was difficult as the zweig and Sahar (1962) and Kreshover et al. (1958) gingivae were red, swollen, bled easily, and were found that children with hypoplastic teeth had a painful during brushing. The dentitions of the 2 male greater dmf rate than those without hypoplasia and siblings were unaffected, with minimal caries activ- suggested that hypoplastic teeth may be more sus- ity. The mother was edentulous and described her ceptible to dental caries than normally calcified teeth. own teeth as weak and thin with a tendency to crack

152 ASYMMETRICAL GROSS TOOTH DEFECTS: Symons and Gage FIG la. Gross tooth destruction and poor gingival health FIG lb. Teeth in the lower left quadrant were severely was evident in the left quadrant. decayed and gingival health was poor. The teeth in the right quadrant showed demineralization of the enamel in the gingival third. shortly after emergence. Consequently they were re- moved early. On examination the child appeared healthy, of Electrophoresis of the dentine collagen peptides normal height and weight with no detectable body was performed on primary teeth on the left side of asymmetry. The right dental quadrants seemed nor- the mouth. A piece of dentine from the exfoliated mal with teeth having reasonable crown height and lower left lateral incisor was crushed to a powder and good occlusion. The teeth in the left quadrants were dialysed with 24-hr changes of 0.5 M EDTA pH 7.4 severely worn, occlusal enamel was absent and ex- at 4°C until the atomic absorption of the extracts for posed carious dentine was evident on the primary calcium at 422.7 nm was minimal. The residue was canines and molars (Figs la, b). Loss of interarch dis- washed several times with distilled water, spun down, tance had occurred between the left buccal segments and lyophilized. due to wear and reduction in crown height (Fig 2). Ten mg of the freeze-dried residue was cleaved The gingivae on the left side were inflamed, swol- with cyanogen bromide (CNBr-substrate ratio 4:1) len, and associated with plaque deposits. in 70% formic acid (substrate concentration 10 mg/ Radiographs revealed bone loss around the pos- ml) for 4 hr at 40°C. At the completion of the reaction terior teeth on the left side, caries, absence of max- the mixture was diluted with 20 Vol of distilled water illary second premolars, and a poorly forming upper and freeze dried to remove both acid and CNBr. The right lateral incisor that appeared to be a peg lateral sample then was dissolved in 0.625 M Tris-HCl Buffer incisor (Figs 2, 3). containing 2% (W/V) SDS and loaded into the sample The treatment consisted of instructions in oral wells of a polyacrylamide gel. hygiene, dietary advice, systemic fluoride, and rou- At completion of the electrophoresis the gels were tine operative therapy. A stainless steel crown was stained with silver stain and then were scanned on placed on the maxillary left primary molar and after the light table of an ultra scan laser densitometer with caries removal glass ionomer restorations were placed a fixed wavelength of 633 nm. The densitometric pro- to protect the severely worn teeth. The oral hygiene files show that the collagen obtained was identical to improved but the gingivae on the left side remained that obtained from normal primary dentine. inflamed since the patient resisted thorough cleaning in this region. Case 2 The patient was recalled regularly and by age 7 A 2V2-year-old Caucasian female was referred to years was well motivated. Oral hygiene had im- the Children's Dental Clinic for management of gen- proved but she developed a preference for sweet eralized hypoplasia of the primary teeth. A medical snacks. The first permanent molars emerged in all history reported occasional ear infections which were quadrants and appeared free of any defects as were treated with antibiotic therapy. The patient had not the 2 lower central incisors (Figs 3a, b). The severely received any radiation therapy, was healthy, born at worn primary teeth were free from symptoms but full term, and was of average height and weight. The most of the protective glass ionomer cement resto- child resided in a nonfluoridated area and had not rations had been worn away. taken any fluoride supplements. The mother breast-

PEDIATRIC DENTISTRY: June 1987/Vol. 9 No. 2 153 FIG 2. OPG radiograph showing absence of upper second FIG 3a. Upper quadrants 3 years after the initial appoint- molars and a poorly forming right lateral incisor. ment. The first permanent molars are erupting and are free of defects. fed her daughter until the age of 14 months, per- mitting the child to fall asleep during feeding. No An asymmetry in the distribution of this genetic de- particular side was favored during sleep. Sucrose was fect was observed (Fig 6). This patient also has a con- ingested, mainly in the form of fruit juices (they were genitally missing maxillary right lateral incisor. The slowly withdrawn after the initial dental appoint- medical history was not significant. ment in the pedodontic clinic). On examination, most primary teeth were present, the upper left primary Discussion second molar was erupted and the lower left primary Asymmetrical gross tooth destruction is unusual second molar was erupting. Minimal plaque was pres- and may be caused by a variety of conditions. In the ent and the gingivae appeared healthy. Smooth sur- patients in this report, the structure of the teeth may face, early carious lesions were evident on the buccal have been affected at various stages due to genetic surfaces of most teeth and the teeth on the left side influences, pre-eruptive, or posteruptive factors which were abraded. Preventive treatment was instigated resulted in the asymmetrical distribution of tooth de- and the mother was instructed in brushing the child's struction. teeth and given dietary advice. The patient was re- As would be expected with a genetic disorder, called at three monthly intervals. The dentitions of the condition should affect all quadrants equally. The two older brothers were unaffected, with minimal first 2 cases show severe tooth destruction unilaterally caries activity and no other members of the family appeared to be similarly affected. At age 3'/2 years the teeth on the left side showed increased wear, while teeth on the right side were minimally abraded (Figs 4a, b). Buccal lesions were present on all teeth, with the left side more severely affected (Figs 5a, b). While caries was not detected on the occlusal surfaces of the left molars, occlusal wear was evident with dentine exposed on the first molars. The enamel covering the occlusal surfaces of the sec- ond molars on the left side was flecked and worn (Fig 4b). It appeared that the left primary second molars erupted with a defect in the enamel which was not due to poor oral hygiene or poor diet. Case 3 A 17-year-old Caucasian female was referred to the clinic for treatment of hypoplastic permanent FIG 3b. The first permanent molars and central incisors teeth. The condition was diagnosed as hypoplastic, are erupting in the lower quadrants. The permanent teeth vertical striping X-linked amelogenesis imperfecta. appear to be free of any defect.

154 ASYMMETRICAL GROSS TOOTH DEFECTS: Symons and Gage FIG 4a. All primary teeth were present in the upper FIG 5a. Buccal lesions were present on all teeth on the quadrant. Wear of occlusal and lingual surfaces of anterior right side. teeth was evident on the left side.

also been regarded as part of an X-linked disorder or and therefore, it is assumed, may exclude inheritance as part of various syndromes2 as observed in Case 3. as a causative factor. In Case 3 it is interesting to Environmental factors may further complicate deter- observe that a genetic condition, amelogenesis im- mination of a genetic basis for anomalies of the den- perfecta, affected all permanent teeth, but teeth in the tition as they may produce a phenotype similar to right quadrants were more severely hypoplastic. that caused genetically. In the first case, the absence Hypodontia is often considered to be a variant of the maxillary premolars, the presence of a peg- of the norm, an isolated trait or an expression of a shaped lateral incisor, and the mother's history of more complex syndrome (Burzynski and Escobar poorly formed teeth point to a possible genetic etiol- 1983). The genetic basis for the absence of second ogy despite the asymmetrical distribution of tooth premolars has not been determined. However, agene- destruction. sis of the maxillary lateral incisors has been reported If enamel hypoplasia, due to an environmental to be an autosomal dominant trait which may be high- disturbance of the ameloblasts, is a factor in the first ly variable in expression and may show reduced pen- 2 cases of tooth destruction, it may have been a local etrance (Shapiro and Jorgenson 1983). Variations re- disturbance due to localized trauma rather than sys- ported include unilateral or bilateral agenesis and temic in origin. If hypoplasia, though microscopic in reduction in tooth size resulting in bilateral or uni- 1 lateral peg-shaped lateral incisors. Hypodontia has 1 Burzynski and Escobar 1983; Dixon and Stewart 1976; Shapiro and Jorgenson 1983. 2 Brown 1983; Burzynski and Escobar 1983; Shapiro and Jorgenson 1983.

FIG 4b. Lower quadrant showing greater wear of the den- tition on the left side. White flecked enamel was observed FIG 5b. Buccal lesions were more severe and affected all on the lower left primary second molar. teeth on the left side.

PEDIATRIC DENTISTRY: June 1987/Vol. 9 No. 2 155 have resulted from abnormal jaw function. The great- er tooth destruction on this side may have arisen from eating habits combined with reduced plaque removal. Conclusion The etiology of this asymmetrical gross tooth de- struction may have a multifactorial basis. Although caries distribution was asymmetrical, inheritance as a causative factor for these cases cannot be excluded. In the first case the mother had apparently suffered from a form of defective tooth structure. The absence of maxillary second premolars and presence of a peg lateral incisor indicated the possibility of a genetic anomaly. Pre-eruptive influences may have resulted FIG 6. Hypoplasia was more severe on the right side in in hypoplasia of the enamel surface, increasing the this patient with amelogenesis imperfecta. The right lateral susceptibility of the tooth structure to decalcification. incisor is congenitally missing. Abnormal feeding habits and poor oral hygiene with- in the affected area may have reduced the resistance of the tooth structure to dental caries. The first per- size, is generally distributed to all the primary teeth, manent molar teeth appeared normal and may be local oral habits may have increased the susceptibility maintained in good health if the patient pays special of the left quadrants to caries and subsequent tooth attention to oral hygiene and adopts a low cariogenic destruction. diet. In nursing bottle caries the 4 maxillary anterior The etiology of the hypoplasia observed in the primary teeth are most affected while the 4 mandib- second case has not been determined but it may have ular anterior teeth may exhibit no involvement at all. resulted from a systemic illness or be of a genetic The canines and first molars may also be affected origin in which 1 side is more affected than the other. (Dilley et al. 1980; Ripa 1978). Drinkard and Dilley The etiology of the hypoplasia affecting the per- (1982) in a case report were able to describe how a manent teeth in the third case is genetic. The con- child with an unusual habit of retaining a piece of dition is inherited as an X-linked trait with females banana in the mouth day and night obliterated the exhibiting alternating bands of hypoplastic and nor- typical pattern of nursing caries. mal enamel consistent with the lyonization effect of In the first case of asymmetrical tooth destruction genes on the X-chromosome in heterozygous females. presented in this paper the patient may have favored There is usually no homology for similarly affected eating on 1 side more than the other. If a pacifier was teeth on each side of the mouth. The apparent in- administered at bedtime, the child, lying on her left creased severity on 1 side of the mouth could be due side, may have pooled food on the left side of the to variation in gene penetrance. mouth with the teat positioned between the occlusal surfaces of the posterior teeth. The bulk of the tongue Dr. Symons is a lecturer, dentistry for children, and Dr. Gage is may have been pushed to the right, protecting the a senior lecturer, restorative dentistry, University of Queensland, teeth on the right side. The mother stated that on Queensland, Australia. Reprint requests should be sent to: Dr. Anne L. Symons, University of Queensland, Dental School, Turbot St., emergence the teeth failed to form properly and Brisbane, Queensland, Australia 4000. chipped away as they emerged. Other parents whose children have suffered from nursing caries have made Brown KS: Evolution and development of the dentition. Birth De- similar observations (Johnsen 1982; Kotlow 1977). fects 19:29-66, 1983. With the progression of the carious process, sen- Burzynski NJ, Escobar VH: Classification and genetic of numeric sitive dentine was exposed and this possibly resulted anomalies of dentition. Birth Defects 19:95-106, 1983. in reduced plaque removal. Plaque accumulation and Dilley, GJ, Dilley DH, Machen JB: Prolonged nursing habit: a pro- irritation on the left side would accelerate the carious file of patients and their families. J Dent Child 47:102-8, 1980. process and gingival inflammation, increasing the se- Dixon GH, Stewart RE: Genetic aspects of anomalous tooth devel- verity of the condition on that side. opment, in Oral Facial Genetics, Stewart RE, Prescott GH, eds. In the second case reported the lower incisors St Louis; CV Mosby Co, 1976 pp 124-50. were affected by caries. It is unlikely that this caries Drinkard C, Dilley DCH: Rampant caries as a result of a bizarre resulted from nursing habits and may be due to caries food habit: a case report. Pediatr Dent 4:131-34, 1982. superimposed on enamel hypoplasia of the primary Johnsen DC: Characteristics and backgrounds of children with dentition. The wear of the teeth on the left side may "nursing caries." Pediatr Dent 4:218-24, 1982.

156 ASYMMETRICAL GROSS TOOTH DEFECTS: Symons and Gage Kotlow LA: Breast feeding: a cause of dental caries in children. J Shapiro SD, Jorgenson RJ: Heterogeneity in genetic disorders that Dent Child 44:192-93, 1977. affect the orofacies. Birth Defects 19:155-66, 1983. Kreshover SJ, Clough OW,Bear DM:A study of prenatal influences Stewart RE, Witkop CJ, Bixler D: The dentition, in Pediatric Den- on tooth development in humans. J Am Dent Assoc 56:240- tistry, Scientific Foundations and Clinical Practice, Stewart RE, 48, 1958. Barber TK, Troutman KC, Wei SHY, eds. St Louis; CV Mosby Ripa LW: Nursing habits and dental decay in infants: "nursing Co, 1982 pp 87-134. bottle caries." J Dent Child 45:274-75, 1978. Rosenzweig KA, Sahar M: Enamel hypoplasia and dental caries in the primary dentition of prematuri. Br Dent J 113:279-80,1962.

Forensics identifies Custer’s last scout

Using forensic techniques, archaeologists determined that bones and teeth found at the site of Custer’s last stand in Montanawere those of a mixed-bloodperson whowas between 35 and 40 years of age, and who smokeda pipe. Michel "Mitch" Boyer, who had a French father and a Sioux mother, was the only person in Lt. Col. Custer’s commandwho fits that description. Boyer was the cavalry leader’s scout and interpreter. To substantiate the identification, archaeologists used television cameras to superimpose a picture of the bones onto the only knownphoto of Boyer. The upper jaw bone was found by a tourist and more bone fragments were found when the Little Bighorn site was excavated in 1984 as part of a battlefield survey. A bullet also was found, along with buttons from civilian clothes, which the nonuniformed Boyer would have been wearing.

U.S. cigarette consumptiondeclines

The United States Department of Agriculture reported the Americans’ total cigarette consumption rose 70%from 1950 to 1981 and then fell about 9%from 1981 to 1986. The report predicts that total cigarette smoking is expected to decline the remainder of this decade becauseof tax increases, health concerns, and smokingrestrictions. One exampleof new restrictions is the government’s ban of smoking cigarettes, pipes, and cigars in federal buildings, except in designatedareas, whichwent into effect February,1987. Cigar and pipe tobacco use also has droppedsteadily since 1970. Use of snuff and chewing tobacco, although gaining in popularity the past decade, may decline in the rest of this decade, the report adds, because federal excise taxes have been placed on smokeless tobacco products. Also, television and radio advertisements for these products are now prohibited, and effective February, 1987, 3 rotating warning labels will appear on smokelesstobacco containers and in print advertisements.

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